Distribution coefficients of phthalates between absorption fiber and water and its using in quantitative analysis

Solid-phase microextraction (SPME) employing absorption type fibers coupled to gas chromatography was used to extract phthalic acid esters from water samples. Distribution coefficients between water and polydimethylsiloxane (K-fw(PDms)) and polyacrylate (K-fw(PA)) for these compounds were determined. To estimate the values of K-fw for compounds of the same class, which did not undergo experiments, it is proposed to use an empirical two-parameter equation in which various physico-chemical and structural characteristics weakly correlated with each other are used as descriptors. K-fw values calculated on the basis of correlation with distribution coefficients in other heterogeneous systems correspond to the values determined experimentally. Distribution coefficients in polyacrylate/water system were used for quantitative determination by SPME-GC-FID method of phthalates in raw and purified municipal wastes which come from a wastewater purifying plant in Bialystok. Concentration of the four phthalates detected in the wastewater (di-n-propyl phthalate, diisobutyl phthalate, di-n-butyl phthalate and di-2-ethylhexyl phthalate) ranged from 1.5 to 50 mu g/l. During a purification process, decomposition of phthalates with higher polarity is the fastest whereas that of di-2-ethylhexyl phthalate is the slowest. (c) 2005 Elsevier B.V. All rights reserved.